System and process for adjusting a zero point of a seat load sensing system

• US 20070010935A1
• Filed: 07/08/2005
• Published: 01/11/2007
• Est. Priority Date: 07/08/2005
• Status: Abandoned Application

• Current Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Hibner, Christopher, Aldeeb, Walid, David, Raymond
• Application Number:
  US11/177,656
• Publication Number:
  US 20070010935A1
• Time in Patent Office: Days
• US Class Current: 701/124
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015

Abstract

A process for adjusting the zero point of a system (10) for sensing weight on a seat (12) of a vehicle includes the steps of correcting only negative zero points errors during an ignition cycle of the vehicle and correcting positive zero point errors after the vehicle ignition cycle ends.

Claims

1. A process for adjusting the zero point of a system for sensing weight on a seat of a vehicle, the process comprising the steps of:

correcting only negative zero points errors during an ignition cycle of the vehicle; and

correcting positive zero point errors after the vehicle ignition cycle ends.

2. The process of claim 1, wherein said step of correcting only negative zero point errors comprises the steps of:

determining a sensed load on the vehicle seat;

determining a negative zero point error in response to determining a negative sensed weight on the vehicle seat; and

zeroing the sensed weight in response to determining the negative zero point error.

3. The process of claim 2, further comprising the step of repeating said steps of determining a sensed load, determining a negative zero point error, and zeroing the sensed weight throughout the duration of the ignition cycle.

4. The process of claim 2, wherein said step of zeroing the sensed weight comprises the step of zeroing the sensed weight in response to determining that the negative zero point error is within a predetermined range.

5. The process of claim 4, wherein said predetermined range is zero to −

10 kilograms.

6. The process of claim 2, wherein said step of zeroing comprises zeroing the sensed weight in response to determining that the negative zero point error exists for at least a predetermined time.

7. The process of claim 6, wherein said predetermined time is at least 0.5 seconds.

8. The process of claim 2, wherein said step of determining a sensed weight comprises determining the sensed weight in response to an output of a seat weight sensor associated with the vehicle seat.

9. The process of claim 1, wherein said step of correcting positive zero point errors comprises the steps of:

determining an unoccupied condition of the vehicle seat;

determining a sensed load on the vehicle seat in response to determining the unoccupied condition of the vehicle seat;

determining a zero point error if the sensed load on the vehicle seat is within a predetermined range; and

zeroing the sensed weight in response to determining the zero point error.

10. The process of claim 9, wherein said predetermined range includes both positive and negative sensed loads.

11. The process of claim 9, wherein said predetermined range is −

4.0 kilograms to +4.0 kilograms.

12. The process of claim 9, wherein said step of determining an unoccupied condition of the vehicle seat comprises at least one of the following steps:

determining that a predetermined amount of time has elapsed after the vehicle ignition cycle ends;

determining that a seat belt associated with the vehicle seat is in an unlatched condition; and

determining that the sensed load on the vehicle seat has not fluctuated for a predetermined amount of time after the vehicle ignition cycle ends.

13. A process for adjusting the zero point of a system for sensing weight on a seat of a vehicle, the process comprising the steps of:

determining a sensed load on the vehicle seat without regard to whether the seat is occupied;

determining a negative zero point error in response to determining a negative sensed weight on the vehicle seat;

zeroing the sensed weight in response to determining the negative zero point error; and

repeating said steps of determining a sensed load, determining a negative zero point error, and zeroing the sensed weight throughout an ignition cycle of the vehicle.

14. The process of claim 13, wherein said step of zeroing the sensed weight comprises the step of zeroing the sensed weight in response to determining that the negative zero point error is within a predetermined range.

15. The process of claim 14, wherein said predetermined range is zero to −

10 kilograms.

16. The process of claim 13, wherein said step of zeroing comprises zeroing the sensed weight in response to determining that the negative zero point error exists for at least a predetermined time.

17. The process of claim 16, wherein said predetermined time is at least 0.5 seconds.

18. The process of claim 13, wherein said step of determining a sensed weight comprises determining the sensed weight in response to an output of a seat weight sensor associated with the vehicle seat.

19. The process of claim 13, further comprising the steps of:

determining an unoccupied condition of the vehicle seat at a predetermined time after the vehicle ignition cycle ends;

determining a sensed load on the vehicle seat in response to determining the unoccupied condition of the vehicle seat;

determining a zero point error if the sensed load on the vehicle seat is within a predetermined range; and

zeroing the sensed weight in response to determining the zero point error.

20. The process of claim 19, wherein said step of determining an unoccupied condition of the vehicle seat comprises at least one of the following steps:

determining that a predetermined amount of time has elapsed after the vehicle ignition cycle ends;

determining that a seat belt associated with the vehicle seat is in an unlatched condition; and

determining that the sensed load on the vehicle seat has not fluctuated for a predetermined amount of time after the vehicle ignition cycle ends.

21. The process of claim 19, wherein said predetermined range is −

4.0 kilograms to +4.0 kilograms.

22. A vehicle seat weight sensing system comprising:

a seat weight sensor associated with a vehicle seat;

a controller operative to determine a sensed weight on the vehicle seat in response to an output from said seat weight sensor, said controller comprising;

means for correcting only negative zero points errors during an ignition cycle of the vehicle; and

means for correcting positive zero point errors after the vehicle ignition cycle ends.